Licensing of intellectual property rights like patents, trademarks, industrial designs, or copyrights as well as of know how is one of the most important means for granting and assigning use of these rights to third parties. Due to the lack of its own regulations, the licensing law has been developed on the basis of case law. The licensing agreement as it is a contractual obligation which is not individually regulated, is related to several types of agreements regulated in the German Civil Code, as, for example, rental agreements, tenancy agreements, usufruct of rights, company or partnership agreements, or sales agreements. However, as to licensing of patent rights, § 15 para. 2 PatG provides a legal basis: (1) The right to the patent, the right to granting of the patent and the right from the patent are devolved to the inheritors. They can be transferred to third parties partially or completely. (2) The rights according to paragraph 1 partially or completely can be subject to an exclusive license or a non-exclusive license for the area of application of this law or for a part of the latter. As far as a licensee infringes a confinement of his license according to sentence 1, the right from the patent can be enforced. (3) A transfer of rights or the granting of a license does not affect licenses which have been granted previously to third parties. As evident from the above, all different kinds of license types are possible, as exclusive licenses or non-exclusive licenses, licenses with territorial or temporal restrictions, or licenses comprising restrictions as regards content.